The present invention refers to a rotary feeder for bulk material or liquids, and in particular to a rotary feeder of the type having a housing with at least one housing inlet for introduction of material and one housing outlet for discharge of material, with a rotor being sealingly and rotatably supported in the housing and including at least one passageway extending between an inlet port and an outlet port and alternately connectable with the housing inlet and the housing outlet.
A rotary feeder of this type is known from U.S. Pat. No. 5,094,403. The rotor which is rotatable about a vertical axis is of similar design as a revolver drum and thus contains numerous internal chambers or passageways extending axially from one end face to another. The rotor housing includes an upper flange plate, with a feed hopper being mounted thereto, and a lower flange plate which is connected to an outlet conduit. Through rotation of the rotor, the inlet ports of individual passageways communicate successively with an inlet in the upper flange plate for introduction of material. After being rotated by an angle of rotation of 180.degree., the passageways thus filled with bulk material arrive with their outlet ports at the housing outlet which is arranged suitably offset in the lower flange plate of the rotor housing.
German patent no. DE 35 42 487 describes a rotary feeder with a rotor which is also provided with axial passageways. In contrast to the previously described rotary feeder, the inlet and outlet ports of the passageways extend radially toward the circumference of the rotor and have different diameter at the inlet side and outlet side. Moreover, the rotor housing includes at the inlet side and at the outlet side an annular chamber with pertaining control bushing which includes circumferentially offset inlet and outlet ports via which in dependence on the rotation of the rotor the passageways are connected with either the annular chamber at the inlet side or the annular chamber at the outlet side.